less than c++ code example

Example 1: c++ what is %

x = 11 % 3;

Example 2: using of and || c++

x = y = z = 5;

Example 3: x += c++

int main ()
{
  int a, b=3;
  a = b;
  a+=2;             // equivalent to a=a+2
  cout << a;
}